[Python] Update python's version (#63)

README.md

@@ -10,7 +10,7 @@
   <!-- [![Build Status](https://travis-ci.org/PaddleCV-SIG/PaddleRS.svg?branch=release/0.1)](https://travis-ci.org/PaddleCV-SIG/PaddleRS) -->
   <!-- [![Version](https://img.shields.io/github/release/PaddleCV-SIG/PaddleRS.svg)](https://github.com/PaddleCV-SIG/PaddleRS/releases) -->
   [![License](https://img.shields.io/badge/license-Apache%202-blue.svg)](LICENSE)
-  ![python version](https://img.shields.io/badge/python-3.6+-orange.svg)
+  ![python version](https://img.shields.io/badge/python-3.7+-orange.svg)
   ![support os](https://img.shields.io/badge/os-linux%2C%20win%2C%20mac-yellow.svg)
 </div>
 
@@ -221,4 +221,3 @@ PaddleRS是遥感科研院所、相关高校共同基于飞桨开发的遥感处
 }
 ```
 
-

setup.py

@@ -16,7 +16,7 @@ import setuptools
 
 DESCRIPTION = "Awesome Remote Sensing Toolkit based on PaddlePaddle"
 
-with open("README.md", "r") as fh:
+with open("README.md", "r", encoding='utf8') as fh:
     LONG_DESCRIPTION = fh.read()
 
 with open("requirements.txt") as fin:
@@ -32,6 +32,7 @@ setuptools.setup(
     long_description_content_type="text/plain",
     url="https://github.com/PaddleCV-SIG/PaddleRS",
     packages=setuptools.find_packages(),
+    python_requires='>=3.7',
     setup_requires=['cython', 'numpy'],
     install_requires=REQUIRED_PACKAGES,
     # [
@@ -41,7 +42,9 @@ setuptools.setup(
     #     'openpyxl', 'gdal'
     # ],
     classifiers=[
-        "Programming Language :: Python :: 3",
+        "Programming Language :: Python :: 3.7",
+        "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
         "License :: OSI Approved :: Apache Software License",
         "Operating System :: OS Independent",
     ],